Evaluation of Large-Scale Housing Projects in Terms of ...€¦ · using flat roofs [8]. Building with domes and vaults cast large amounts of shadow (Figs. 3 and 4). The housing units

Journal of Civil Engineering and Architecture 10 (2016) 157-165 doi: 10.17265/1934-7359/2016.02.004

Evaluation of Large-Scale Housing Projects in Terms of

Their Compatibility to Criteria of Environmental Design

Yasser Aref1 and Tasneem M. Khalil2

1. Department of Architecture, Faculty of Engineering, Menoufia University, Menoufia 32511, Egypt

2. Water and Sewage Company, Menoufia 32511, Egypt

Abstract: The design and execution of large-scale housing projects always have negative environmental impacts in terms of excessive consumption of non-renewable energy resources and environmental pollution. These negative impacts are multiplied in the case of large-scale housing projects where a large number of standardized units are implemented in a repeated manner. This proposed paper will study and evaluate the environmental impacts of large-scale housing projects according to criteria of environmental design. The case study project is Haram City that is a housing project for small low-income families. The project consists of 50,000 housing units and is located in 6th of October City, which has a hot dry desert climate that necessitates special design considerations and applications of environmental design concepts. The project will be analyzed and evaluated in terms of site layout, design of buildings, orientation, materials used, construction techniques, thermal behavior, landscaping, etc. Key words: Green architecture, environmentally-friendly buildings, low-cost housing projects, environmental design concepts.

1. Introduction

The design and construction of buildings usually

cause a lot of environmental degradations. Buildings

consume large amounts of energy and water, and they

produce harmful wastes. Many buildings create

unhealthy internal environments that cause inhabitants

to become sick and uncomfortable physically and

psychologically. The processes of design and

construction of buildings need to be reconsidered to

assess their impact on health and the environment.

These processes need to be evaluated in accordance to

environmental-friendly buildings standards. This

paper aims to achieve some conclusions and strategies

that can be recommended and applied to the future

designs of housing projects. To achieve these goals,

the research will review general concepts of green

architecture and concepts of environmentally-friendly

designs, setting up the evaluation criteria for

environmentally-friendly designs and, finally, study in

Corresponding author: Yasser Aref, associate professor,

research fields: sustainable architectural and conservation of cultural heritage.

detail one of the large-scale housing projects in Egypt.

2. Characteristics of Sick Buildings

Sick buildings have three main characteristics:

(1) They consume excessive amounts of energy and

natural resources, i.e., energy used to construct a

building can be equal to the required energy to run it

for a period of 10~20 years [1]. The construction

industry consumes about 40% of the total energy

consumption in the world. Moreover, the building

sector, including all processes of construction,

manufacturing, operating and others, consumes

annually about 16% of potable water [2];

(2) The construction industry is responsible for one

third of the amount of carbon dioxide emissions stored

and about two thirds of the amount of acid rain from

sulfur dioxide and nitrogen oxide [2]. This causes

environmental pollution and disturbs the ecosystem;

(3) The negative impact on human health is caused.

Some building materials, such as polyurethane, foam

wallpaper, vinyl and petrochemical-based paints or

plastics, can be harmful to human health [3].

Moreover, some soils on the building site may emit

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Evaluation of Large-Scale Housing Projects in Terms of Their Compatibility to Criteria of Environmental Design

158

radon [4]. In order to avoid the disadvantages of the

sick buildings, the concept of green architecture and

its principles must be studied and applied.

3. Principles of Green Architecture

Green architecture is a process of designing

buildings with respect for the environment. It aims to

reduce the consumption of energy, materials and

resources while maximizing harmony with nature [3].

Green architecture has five main principles.

3.1 Saving Energy

Green architecture has a principle of saving energy

by reducing the energy required in the construction of

the buildings, increasing energy efficiency, depending

on natural energies, such as sun, wind, waves,

biomass and water [5], raising the efficiency of the

surrounding of the building and optimizing the

building orientation [3].

3.2 Adapting to Local Climate

The building design should provide protection from

the climate and provide a suitable internal atmosphere

for human activities [6].

3.3 Minimizing the Consumption of New Resources

Green buildings minimize the consumption of new

resources by using recyclable and biodegradable

building materials [3]. They also use durable local

building materials to minimize the energy used for

transportation and have a long lifespan which requires

less maintenance [2]. Water consumption can be

reduced by recycling and treating waste water, which

is known as grey water, and also collecting and

reusing rainwater [5].

3.4 Respect of Surrounding Site

This is achieved by minimizing substantial changes

to the site, lowering the footprint of the building,

avoiding building on agricultural lands and

minimizing pollution during construction process [7].

3.5 Comprehensive Design

The principles of green architecture must be applied

in an integrated manner during the design and

construction processes, taking into consideration the

wider context within a comprehensive planning

approach [6].

4. Case Study

In this part, the project of Haram City (or Pyramid

City) will be studied and evaluated for its achievement

of the objectives and principles of green architecture

and to examine how far it is environmentally-friendly.

This project was selected because it is a new, large

housing project aimed for low income families. Due

to the large number of units (50,000 units), the impact

of the project on site, users and the environment is

critical.

In 2006, OHC (Orascom Housing Communities), in

a joint venture with Homex, an integrated home

development company focused on affordable housing

headquartered in Mexico, launched the project. For

this project, OHC was allocated approximately

8,400,000 m2 of land in 6th of October City, in the

vicinity of Cairo. The town infrastructure will include

educational, health, commercial and entertainment

services. Actual construction started in spring 2007

and the city was inhabited in the fall of 2008.

Construction work on two zones out of the planned

eight zones was completed, and the main water line,

electricity supply and sewage plants have been

secured.

5. Analysis of Criteria of an Environmentally-Friendly Building

5.1 Using Natural Energy

5.1.1 Building Orientation

It is preferable to position the longest façades of the

building on the east-west axis, i.e., the north façade is

exposed to the lowest amount of heat in summer while

the south façade exposed to the highest amount of


159

heat in winter [8]. Building orientation has not been

highly considered in the planning of Haram City,

where the typology of units consists of four units

which are assembled around a staircase (Fig. 1).

Setting the layout of the blocks in rows resulted in

opposite directions for units.

5.1.2 The Building Form

In hot arid areas, the ideal ratio of the two sides of

buildings ranges from 1:1.3 to 1:1.6. This ratio deters

the heat in the summer and stores it in the winter [8].

In the studied model, the elongation percentage is

1:1.4 which lays within the recommended

ratios (Fig. 2).

5.1.3 The Building Mass

Shadow on buildings can save up to more than 30%

in consumed energy [6]. Shadow can be maximized

by articulating the mass of the buildings and avoiding

using flat roofs [8]. Building with domes and vaults

cast large amounts of shadow (Figs. 3 and 4). The

housing units in Haram City project have a one-sided

open courtyard, 4 m wide. The court provides shade

and allows for wind movement and is used as a

bioclimatic feature. Windows are recessed about

10cm. The ground floor is protected by the balcony of

Fig. 1 The direction of wind around site area. Source: the authors, base master plan administration of Haram City.

Fig. 2 Building elongation (units in m). Source: the authors.

first floor (Fig. 5). Experiments state that when the

external façade area (F) is less than the volume (V),

thermal exchange with the external surrounding is

minimal. This results in saving energy. This

phenomenon is applied in designing attached or

semi-attached buildings [9]. For the Haram City

Project:

External surface: F = 6,011.6 m2;

Volume of the housing block: V = 6,325 m3;

F/V = 0.9.

According to this result, the buildings of the project

fall within the recommended ratio which implies that

they use less energy for conditioning the internal

spaces.

5.1.4 Organization of Internal Space

Services are preferably located to the south and

west to insulate heat while bedrooms and living spaces

Fig. 3 Shadows resulted from the differences of building height. Source: the authors.

Fig. 4 The effect of the surface shape on shadows amount [8].

Sun rays direction

Shadowed area

Weak concentration

of rays Strong

concentration of rays

15.4

21.3


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Fig. 5 Shadows falling on the building façade. Source: the authors.

Fig. 6 Configuration of housing units in the upper floor.

Source: the authors.

Fig. 7 Plan for the first floor (units in m). Source: project administration of Haram City.

are preferably be located to the north-east or east

where they catch cool breezes and receive natural

light without heat gain [8]. Consequently, some of the

units of Haram City achieved the proper orientation

while others did not. This is, of course, due to the

large number of units and other planning

considerations (Figs. 6 and 7).

5.1.5 Walls

Internal and external walls should be thick and

massive in the hot, dry climate. Wall thickness of

Haram City buildings is 22 cm. Walls are made of red

clay bricks which have a large thermal capacity

(25.2 W/m2·°C) and have a delay of the thermal

transition time of approximately 4 h and 16 min [10].

The higher the thermal capacity of the wall, the less

heat transmission inside the building [11]. The

minimal total cost per unit area of the walls, including

brick and mortar price, as well as workers salaries,

plus operating costs is equivalent to a wall thickness

of 0.34 m, i.e., one and a half bricks (Fig. 8) [12]. The

surrounding land surface and landscaping in Haram

City, which is treated by planting green areas of grass,

scatters solar radiation reflected from the walls.

5.1.6 Openings

To allow for maximum air circulation, it is

recommended that inlet and outlet openings have

different areas. The air that enters opening should be

less than the air from outlet opening. The glass area

should not be more than 10% of the floor area and it is

favorable to use sun breakers and curtains to minimize

thermal gain [9]. Most of the rooms of the Haram City

buildings have one opening while living rooms have

two openings in two perpendicular walls. The height

of the windows from the floor is 1.10 m. The area of

glass is about 5% of the floor area and no sun breakers

are used.

5.1.7 Roofs

The gain of thermal energy through the ceiling

depends on the thermal performance of the material

used for its construction [9]. In Haram City, the roofs

are made of red bricks that have low heat absorption.

4 3

2 1

Bedroom

Terrace

3.73

Hall

Kitchen

Bath

Bedroom

3.73

4.35 7.71

4.57

3.02


161

Fig. 8 Relationship between wall thickness (x-axis) and total cost per unit of surface area (y-axis). Source: the authors.

Fig. 9 Variation of heat flux through the dome during 24 h. Source: the authors.

The vaulted shape of the roofs increases the speed of

the air passing on its curved surfaces. This cools the

inside of the building; The vaults have no openings

for the hot air to be discharged during the night [13].

Based on Refs. [12, 14], Fig. 9 illustrates heat loss

through the domes of the buildings during 24 h.

5.2 Environmentally-Friendly Building Materials

Building materials should be

environmentally-friendly. They must consume low

energy in the stage of manufacturing, installation and

maintenance. Building materials should also minimize

internal pollution of the building. The energy

consumption of a building material is based on the

total energy (combination of electrical energy and

thermal energy) needed for producing a unit weight of

the material. The energy consumption of producing a

unit weight of bricks is 2,320 W·h/t [3]. The main

building material used for the foundations, walls and

roofs are locally produced by red bricks, which are

durable and environmentally-friendly. The transfer of

bricks from nearby Bani-Sewaif’s and El-Saf’s

factories does not consume large amounts of energy.

Acrylic paint is used for internal finishing, and

ceramic tiles are used for floorings; Both are not

environmentally-friendly building materials. The first

contains chemicals and the second consumes large

amounts of energy during production phase that are

harmful to the environment.

5.3 Saving Water

Supplying water consumes energy for collecting,

purifying and pumping to the buildings. Haram City is

applying concepts of reusing water. Sewage from basins,

900

800

700

600

500

400

300

200

100

0

C

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 x

Hea

t flu

x q

(W/m

2 )

80 70 60 50 40 30 20 10

0 6 8 10 12 14 16 18

Daily hours


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Fig. 10 Air movement inside a room with two openings. Source: the authors.

Fig. 11 Air movement inside a room with one opening. Source: the authors.

kitchens and showers are collected in a special tank,

treated and reused in watering gardens and pumped

again to flush tanks.

5.4 Air Quality

Pollution of air inside a building is a result of using

chemicals in building materials and finishing, and also

in poorly ventilated buildings [3]. For the openings

layout in Haram City buildings, most of the openings

are facing prevailing winds (Figs. 10 and 11). Some

rooms have more than one opening. This allows more

active air circulation. Air conditioners are rarely used

in Haram City buildings. This prevents the spread of

bacteria and fungi. Even though porous bricks are

used in the building, they are covered which results in

making them less permeable and do not retain

moisture. This did not balance the proportion of

moisture in the surrounding dry climate [15].

5.5 Natural Lighting

Openings represent 8% of room floor area and 10%

of bathroom area. These percentages are in

accordance with local building codes [16]. Roofs,

walls and window frames are textured and painted in

light colors to reflect the sun and reduce glare. Clear

glass panes are used for the windows. This allows the

maximum quantity of the light into the internal space

with the minimum blurring. The glass thickness is

3 mm, its reflection factor is 7%, its absorption is 8%

and its transmission is 85% [13].

5.6 Acoustic Design

The efficiency of walls in preventing noise

transmission depends on their mass and thickness. On

the other hand, floors depend on the degree of surface

absorption [3]. For Haram City buildings, the

thickness of the wall bricks is 22 cm; This is not

enough to insulate noise. In Haram City, bedrooms are

placed inside and overlook pathways between units;

Service areas overlook the stairs, while living rooms

overlook the street. This arrangement provides

bedrooms with the required sound insulation.

5.7 Safety Design of the Building

The site of Haram City is a combination of sandy

and rocky soils. The project is laid out with the

minimum intervention of the land, following natural

contours. A belt of trees is planted around the

buildings to be fenders against unwanted winds. The

design of buildings considers earthquake resistance in

terms of regular mass, using one construction system,

in which the building length is less than 4 times its

width and the limited height [17]. For fire resistance,

the stair serves four flats. The stair is compatible with


163

the fire codes as they have a width of 1.20 m and is

divided into two flights, each flight consists of

10 steps separated by a landing of

1.20 m × 1.20 m [18], in addition to fire extinguishers

which are distributed all over the project.

5.8 Architectural Style Compatible with the Local

Character

Egypt has a hot dry climate, therefore, in Haram

City, thick walls are used. Roofs are covered by

domes and vaults. Local bricks are used as the main

building material. These elements adapt to climate,

protect from sun rays, provide shade and cool the

atmosphere. They are also compatible with the local

architectural character and are inspired by the

vernacular architecture of the area developed by

Hassan Fathi and Ramsis Wissa Wassef in Harrania

and Giza.

5.9 Landscaping and Outdoor Spaces

Grass can filter the air from dust, smog and waste,

and it also improves the hot climate by 30% [7]. It

also minimizes relative humidity and glare [19].

Walkways are made of natural stone masonry.

Vegetation is used wisely with Ficus fences around

the blocks and trees planted in each garden (Fig. 12).

5.10 Master Plan

The master plan of the project is not compact.

However, buildings are quite close to each other,

shading each other and also providing shade for the

narrow walkways. Spaces in front of buildings consist

of large green areas and parking. Each cluster of

buildings is grouped around a green public space.

These public spaces are interrelated by foot paths,

providing a pedestrian network. The height of the

buildings ranges from one floor to four floors and has

a homogeneous visual character.

6. Findings

Buildings should be friendly to the environment by

Fig. 12 The use of shrubs and trees for shading of building façades. Source: the authors.

applying the standards of environmental design. Some

of these standards are achieved by Haram City which

leads to the following conclusions:

Buildings are oriented towards several directions.

The plan is rectangular with a ratio of 1:1.4. It is

directed along the east-west axis. The proper

orientation for some buildings is achieved;

The proportion between the external areas, which

are exposed to weather conditions, to the total volume

is 0.9;

Local red clay bricks with a width of 22 cm are

used as bearing wall structure system. Red bricks are a

local building material with a low consumption of

energy which causes minimum pollution. However,

the best thickness for walls in terms of thermal

comfort and optimum cost should have been 34 cm.

Moreover, walls are not thick enough to prevent the

transmission of noise;

External walls and roofs are painted with light

colors to reflect heat and sun rays;

Roofs are domed and vaulted to cast shadow to

prevent direct sun exposure and create shade

articulated building forms;

The landscape is planted with trees and some

shrubs to control the circulation of the air around or

into the building. This also reduces the heat gain of

the walls. This leads to a saving of about 60% of the

consumption of energy used for cooling or heating;


164

The use of recycled treated grey water for

irrigation and flushing is achieved;

The architectural style of the buildings is

compatible with the local environment through using

roofs with domes and vaults and local materials;

Even though the layout of the site is not compact,

the buildings are close enough to provide shaded and

narrow walkways.

7. Recommendations

Following recommendations are given to future

researches:

To achieve the ideal orientation for units, a

cluster of housing units should be designed with

optimum orientation for each unit, then this cluster is

repeated;

We can utilize renewable energy sources either

directly or indirectly while preparing the architectural

and mechanical designs of the buildings as it

contributes to the reduction of energy consumption in

buildings;

Applying concepts of energy conservation in

design and construction of housing projects should not

deter from providing the required services, comfort

and architectural aesthetics;

Different construction methods and building

materials can be used in the same building according

to the type and use of internal spaces. The spaces used

throughout the day should have thick walls with large

thermal capacity. Spaces with little use may be of

light materials with low thermal capacity;

In designing large-scale housing projects, plans

should be flexible and provide the possibility of

vertical or horizontal extension to accommodate the

increase of family size;

Using high openings in walls and vaults provides

heat discharge and air circulation. The openings size

should prevent the entry of direct sunlight and rain;

Walls must be designed to reach the highest

possible efficiency in terms of providing thermal

comfort while saving energy consumption, as well as

cost. It was found that the lowest total cost for a wall

to save thermal comfort can be obtained by designing

walls of 34-cm thickness.

References

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[2] Al Rafai, M. 2007. “Technical View for Drafting Permanent Reconstruction from Local View.” M.Sc. thesis, Cairo University.

[3] Waziri, Y. 2007. Environmentally Friendly Architectural Design—Towards Green Reconstruction. Cairo: General Egyptian Authority for Books.

[4] Pearson, D. 1991. The Natural House. London: Conran Octopus Ltd.

[5] Bauer, M., Mosle, P., and Schwarz, M. 2010. Green Building—Guidebook for Sustainable Architecture. Berlin: Springer.

[6] El Shahry, A. 2008. “Building Technology and Its Rule in Achieving Thermal Comfort inside Architectural Spaces.” M.Sc. thesis, Cairo University.

[7] Abdou, O. 2000. “Green Architecture: A Holistic Approach.” Medina Magazine 11: 28-31.

[8] Al Wakeel, S., and Serag, M. 1985. Climate and Hot Area Architecture. Cairo: Al Tobgy Press.

[9] Afify, H. M. 2001. “Design Considerations for Rural Housing from the Perspective of Environmental Engineering and Energy Self-Sufficiency.” Presented at the 3rd Conference for the Development of the Egyptian Countryside, Cairo, Egypt.

[10] Aziz, S. 1988. “Thermal Attitude Evaluation as a Tool for Designing Housing Complexes in Egypt.” Ph.D. thesis, Cairo University.

[11] Watson, D., and Labs, K. 1983. Climatic Design. New York: McGraw-Hill Book Company.

[12] Group of Energy and Reconstruction Experts. 1998. Reconstruction and Energy Guide. Cairo: Energy Planning Department.

[13] Ali, A. M. 2006. Climate and Desert Reconstruction. Assuit: Assuit University.

[14] Selim, R. 2003. “The Impact of Building Technology Used in Outer of the Building on Conserving Energy.” M.Sc. thesis, Cairo University.

[15] Baggs, S., and Baggs, J. 1996. The Healthy House. London: Thames and Hudson.

[16] Ministry of Housing, Utilities and Urban Development. 2008. Building Law (No. 119, 2008). Cairo: Ministry of Housing, Utilities and Urban Development.

[17] Housing and Building National Research Center. 2005. Egyptian Code for Designing and Constructing Buildings, No. 204. Cairo: Today’s News Press.


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[18] Housing and Building National Research Center. 2007. Egyptian Code for Fire Protection: Part one. Cairo: Republic House Press.

[19] Abou Seda, H., and Badr, B. 2002. Environment Reconstruction Profession. Cairo: Arab World House.

Documents

Evaluation of Large-Scale Housing Projects in Terms of ...€¦ · using flat roofs [8]. Building with domes and vaults cast large amounts of shadow (Figs. 3 and 4). The housing units